94 J- M- ESSENBERG. 



PLATE IX. 



FIG. 38. Transverse section of testis in late stage of tubule formation (late 

 phase). X 135. 



FIG. 39. Portion of transverse section of testis in late stage of tubule for- 

 mation to show branching tubules. X 205. 



FIG. 40. Transverse section of bifurcated testis, anterior part. X 467. 



FIG. 41. Transverse section of bifurcated testis, posterior part. X 467. 



FIG. 42. Anal fin of indifferent stage. X 55. 



FIG. 43. Anal fin of adult female. X 10. 



FIG. 44. Transverse section of adult gonopod from level A-A, Fig. 46. 

 X 25. 



FIG. 45. Transverse section of adult gonopod from level BB, Fig. 46. 25. 



Symbols : 



ac Acinus or spermatocyst. 



bsc Branch of sex cord. 



bv Blood vessel. 



d^r Dorsal branch of fourth ray. 



ee External epithelium of gonad. 



fep Fin epithelium. 



m Mesentery. 



mch Mesorchium. 



ntc Nest of definitive germ cells. 



p Peritoneum. 



ppgc Primordial germ cells in periphery of testis. 



sc Sex cords. 



sp Spoon-like structures. 



spd Sperm duct. 



t$r Teeth of third ray. 



t^r Teeth of fourth ray. 



v$r Ventral branch of fourth ray. 



ir-ior First to tenth rays of anal fin. 



